JPWO2018131413A1 - Mobile communication system and congestion control method - Google Patents

Abstract

The mobile communication system 1 includes a core network including an MM that manages UE mobility, a plurality of SMs that manage UE sessions, and a plurality of UPs that transmit and receive user data. A mobile communication system in which a plurality of slices are allocated to a UP, and when receiving a connection establishment request including slice type information identifying a slice from a UE, and congestion of the slice based on the slice type information or When congestion of the network to which the slice is connected is specified, a request reply unit 25 that transmits a retransmission request for requesting retransmission of the connection establishment request to the UE is provided.

Description

  The present invention relates to a mobile communication system and a congestion control method.

  Conventionally, standardization of mobile communication systems has been promoted in 3GPP (Third Generation Partnership Project), which is a standardization project. Non-Patent Document 1 below discloses an architecture of a next generation system (NextGen) of a mobile communication system proposed in this standardization project. This architecture is a mobile communication system having functions of MM (Mobility Management), SM (Session Management), and UP (U-Plane), and attach requests (Attach) from UE (User Equipment) which is a user terminal. Request), UE can connect to DNN (Dedicated Network Name), which is a connection destination node, via one MM and multiple slices that are virtual networks composed of multiple SMs and UPs It is comprised so that.

3GPP TR 23.799

  However, in the above-described NextGen architecture, congestion control becomes difficult when communication via a specific slice is congested, and communication efficiency may not be sufficiently improved.

  Therefore, an embodiment of the present invention has been made in view of such a problem, and provides a mobile communication system and a congestion control method that realizes congestion control in units of slices and enables communication efficiency. For the purpose.

  In order to solve the above-described problem, a mobile communication system according to an aspect of the present invention includes a mobility management function unit that manages mobility of a mobile communication terminal, and a plurality of session managements that manage sessions of the mobile communication terminal. A core network including a function unit and a plurality of user data transmission function units that transmit and receive user data used for services to mobile communication terminals, a plurality of session management function units, and a plurality of user data transmission function units; A mobile communication system to which a plurality of slices which are a plurality of virtual networks are assigned, and when receiving a connection establishment request including slice specifying information for specifying a slice from the mobile communication terminal, and slice specifying information The congestion of the slice or the network to which the slice is connected If, comprising a retransmission request transmission section that transmits the retransmission request, the mobile communication terminal requesting the retransmission of the connection establishment request.

  Alternatively, the congestion control method according to another aspect of the present invention includes a mobility management function unit that manages mobility of a mobile communication terminal, a plurality of session management function units that manage a session of the mobile communication terminal, and mobile communication. A virtual network having a core network including a plurality of user data transmission function units that transmit and receive user data used for a service to a terminal, and a plurality of virtual networks for the plurality of session management function units and the plurality of user data transmission function units A congestion control method in a mobile communication system to which a plurality of slices are assigned, when receiving a connection establishment request including slice specification information for specifying a slice from a mobile communication terminal, and based on the slice specification information The congestion of the slice or the congestion of the network to which the slice is connected is specified If a retransmission request for requesting retransmission of the connection establishment request to the mobile communication terminal.

  According to the one aspect or the other aspect, when a connection establishment request is received from a mobile communication terminal, on a slice basis, based on a congestion state of the slice or a congestion state of a network to which the slice is connected A retransmission request is returned to the mobile communication terminal. As a result, it is possible to perform efficient communication by realizing congestion control in units of slices in which a tendency of communication congestion is likely to appear.

  According to the embodiment of the present invention, it is possible to realize congestion control in units of slices and improve communication efficiency.

1 is a diagram showing a system configuration of a mobile communication system 1 according to a preferred embodiment of the present invention. It is a block diagram which shows an example of the hardware constitutions of MM20 of FIG. It is a block diagram which shows the function structure of MM20 of FIG. It is a figure which shows an example of the data structure of the network management information hold | maintained at the information holding part 24 of FIG. It is a figure which shows an example of a data structure of the slice management information hold | maintained at the information holding part 24 of FIG. It is a sequence diagram which shows the procedure of the setting process of the communication path | route of the control data by the mobile communication system 1 of FIG. It is a sequence diagram which shows the procedure of the setting process of the communication path | route of user data by the mobile communication system 1 of FIG. It is a block diagram which shows the hardware constitutions of SM30A concerning a modification. It is a block diagram which shows the function structure of SM30A concerning a modification. It is a figure which shows an example of the data structure of the network management information hold | maintained at the information holding part 34 of FIG. It is a sequence diagram which shows the procedure of the setting process of the communication path | route of the user data in a modification. It is a sequence diagram which shows the procedure of the setting process of the communication path | route of the user data in a modification.

  Embodiments of the present invention will be described with reference to the accompanying drawings. Where possible, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a diagram showing a system configuration of a mobile communication system 1 according to a preferred embodiment of the present invention. As shown in FIG. 1, the mobile communication system 1 is a mobile communication system according to the NextGen architecture, and includes MM (Mobility Management Function Unit), SM (Session Management Function Unit), and UP (User A data transmission function unit) including a core network. The mobile communication system 1 provides a communication function to a user terminal by a virtual server operating in a virtual machine realized on a physical server. In this mobile communication system 1, MM is a node (functional unit) that manages the mobility (movement state) of a UE that is a user's mobile communication terminal, SM is a node that manages a UE communication session, and UP Is a node that transmits and receives user data used for services between the UE and the core network. A plurality of SMs and UPs can be provided in one mobile communication system 1. In the example shown in FIG. 1, two nodes SM30a and 30b are provided as SMs, and two nodes UP40a and 40b are provided as UPs. A plurality of slices that are a plurality of virtual networks are allocated in advance to each of a plurality of arbitrary combinations of SM and UP, and different types of services are provided to the UE 10 in units of one or more slices. The “slice” here is a virtual network or a service network that is logically generated on the network infrastructure by virtually separating the link of the network device and the resource of the node and combining the separated resources. They separate resources and do not interfere with each other. “Service” refers to a service using network resources such as a communication service (private line service or the like), an application service (service using a sensor device such as moving image distribution or an embedded device). For example, in the example shown in FIG. 1, the slice SLa is assigned to the SM 30a and the UP 40a, and the slice SLb is assigned to the SM 30b and the UP 40b. When a service is provided to the UE 10, a communication path (bearer) is established between the UE 10 and the slice, and communication between the UE 10 and a DNN that is a communication destination node is performed via this bearer. Is connected.

  Below, each structure of MM20, SM30a, 30b, and UP40a, 40b is demonstrated. SM30a and SM30b have the same function, and may be described as SM30. Further, UP 40a and UP 40b have the same function and may be referred to as UP 40 in some cases. In addition to the functions described below, MM20, SM30, and UP40 also have general functions included in each element disclosed in “3GPP TR 23.799” or general documents related to mobile communication systems. Shall have. In addition to the functions described below, the MM 20, SM 30, and UP 40 have functions described using the sequence diagrams of FIGS. 6 to 7 and FIGS.

  FIG. 2 shows the hardware configuration of the MM 20, and FIG. 3 shows the functional configuration of the MM 20. As shown in FIG. 3, the MM 20 includes, as functional components, a mobility management function unit 21, a request receiving unit 22, a congestion state specifying unit 23, and an information holding unit (network information holding unit, slice allocation information holding unit) 24. , And a request reply unit (retransmission request transmission unit) 25.

  The block diagram shown in FIG. 3 shows functional unit blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one device physically and / or logically coupled, and two or more devices physically and / or logically separated may be directly and / or indirectly. (For example, wired and / or wireless) and may be realized by these plural devices.

  For example, the MM 20 in one embodiment of the present invention may function as a computer that performs the processing of the MM 20 in the present embodiment. FIG. 2 shows an example of the hardware configuration of the MM 20 according to the present embodiment. The MM 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

  Note that in the description in this specification, the term “apparatus” can be read as a circuit, a device, a unit, or the like. The hardware configuration of the MM 20 may be configured to include one or a plurality of devices illustrated in the figure, or may be configured not to include some devices.

  Each function in the MM 20 reads predetermined software (program) on hardware such as the processor 1001 and the memory 1002 so that the processor 1001 performs an operation to perform communication by the communication device 1004 and data in the memory 1002 and the storage 1003. This is realized by controlling reading and / or writing.

  For example, the processor 1001 controls the entire computer by operating an operating system. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, a register, and the like. For example, the mobility management function unit 21, the request receiving unit 22, the congestion state specifying unit 23, the request returning unit 25, and the like may be realized by the processor 1001.

  Further, the processor 1001 reads a program (program code), software module, and data from the storage 1003 and / or the communication device 1004 to the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least a part of the operations described in the above embodiments is used. For example, the mobility management function unit 21 may be realized by a control program stored in the memory 1002 and operated by the processor 1001, and may be realized similarly for other functional blocks. Although the above-described various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. Note that the program may be transmitted from a network via a telecommunication line.

  The memory 1002 is a computer-readable recording medium and includes, for example, at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), and the like. May be. The memory 1002 may be called a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, and the like that can be executed to perform various processes of mobile communication according to an embodiment of the present invention.

  The storage 1003 is a computer-readable recording medium such as an optical disc such as a CD-ROM (Compact Disc ROM), a hard disc drive, a flexible disc, a magneto-optical disc (eg, a compact disc, a digital versatile disc, a Blu-ray). (Registered trademark) disk, smart card, flash memory (for example, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, and the like. The storage 1003 may be referred to as an auxiliary storage device. The storage medium described above may be, for example, a database, server, or other suitable medium including the memory 1002 and / or the storage 1003. For example, the information holding unit 24 and the like may be realized by the storage 1003.

  The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via a wired and / or wireless network, and is also referred to as a network device, a network controller, a network card, a communication module, or the like. For example, the request reception unit 22 and the request reply unit 25 may be realized by the communication device 1004.

  The input device 1005 is an input device that accepts input from the outside, and the output device 1006 is an output device that performs output to the outside. The input device 1005 and the output device 1006 may be realized by a touch panel display in which both are integrated.

  Each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured with a single bus or may be configured with different buses between apparatuses.

  The MM 20 includes hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA). Alternatively, some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented by at least one of these hardware.

  Next, functions of each functional unit of the MM 20 will be described.

  The mobility management function unit 21 is a part that performs location management of UE 10 located in the mobile communication system 1, authentication control, and setting processing of a communication path of control data or user data between the UP 40 and the UE 10.

  The request receiving unit 22 receives an attach request (Attach Request) for requesting connection establishment of a communication path of control data from the UE 10. At this time, the request reception unit 22 includes service type information (slice identification information) or slice type information (slice identification information) for identifying a slice, and DNN indicating an address of a connection destination node in the attach request. Receive. In response to the reception of the attach request by the request reception unit 22, the mobility management function unit 21 performs a control data session setting process between the UE 10 and the MM 20. Further, the request receiving unit 22 receives from the UE 10 a session request (PDU Session Request) for requesting connection establishment of a communication path for user data following the attach request. At this time, the request reception unit 22 includes service type information (slice identification information) or slice type information (slice identification information) for identifying a slice and DNN indicating the address of a connection destination node in the session request. Receive. In response to the reception of the session request by the request reception unit 22, the mobility management function unit 21 allocates session identification information (PDU-ID) for identifying a session of user data between the UE 10 and the UP 40. Session setting processing via the corresponding slice is performed.

  When the request receiving unit 22 receives an attach request, the congestion state specifying unit 23 identifies a slice corresponding to service type information or slice type information included in the attach request, and congestion of a network to which the slice is connected Identify the state. At this time, the congestion state specifying unit 23 specifies the network to which the slice is connected by referring to the network management information held in the information holding unit 24, and specifies the congestion state of the specified network.

  In FIG. 4, (a) part and (b) part each show an example of the data configuration of the network management information held in the information holding part 24. In the example of the network management information shown in part (a) of FIG. 4, slice type information for specifying a slice connected to the network for each DNN “DNN1” and “DNN2” specifying the connection destination network. “Slice # 1” and “Slice # 2” are associated with each other, and in the example of the network management information shown in part (b) of FIG. 4, DNN “DNN2” and “DNN2” for specifying the connection destination network Are associated with slice type information “Slice # 1” and “Slice # 2” for specifying slices connected to the network. In this way, a plurality of slices can be connected to the same DNN. When the attach request including the slice type information “Slice # 1” is received, the congestion state specifying unit 23 refers to the network management information shown in the (a) part of FIG. 4 and determines the slice “Slice # 1”. The DNN “DNN1” of the connection destination is specified, and the congestion state of the DNN “DNN1” is specified.

  At this time, the congestion state specifying unit 23 may determine the congestion state by measuring the communication delay time between the MM 20 and the DNN, or the congestion state is notified from the DNN, SM30, UP40, or the like. Also good. Further, the congestion state identification unit 23 may identify the congestion state every time an attach request is received, or may perform it in advance (at an arbitrary timing such as periodically). Further, the congestion state specifying unit 23 may specify the DNN of the connection destination of the slice based on the DNN included in the attach request, and specify the congestion state of the specified DNN.

  In addition, when the session request is received by the request receiving unit 22, the congestion state specifying unit 23 identifies a slice corresponding to the service type information or slice type information included in the session request, and determines the congestion state of the slice. Identify. At this time, the congestion state specifying unit 23 specifies the slice by referring to the slice management information held in the information holding unit 24, and specifies the congestion state of the specified slice.

  FIG. 5 shows an example of the data configuration of the slice management information held in the information holding unit 24. In the example of slice management information shown in FIG. 5, for each slice type information “Slice # 1” and “Slice # 2” for specifying a slice, an SM for specifying a combination of SM30 and UP40 assigned to the slice. The identification information and the UP identification information “SM1, UP1”, “SM2, UP2” are associated with each other. In this way, a slice is assigned to each of a plurality of combinations of SM30 and UP40. When the session request including the slice type information “Slice # 1” is received, the congestion state specifying unit 23 refers to the slice management information illustrated in FIG. 5 and refers to the SM30 “assigned to the slice“ Slice # 1 ”. SM1 ”and UP40“ UP1 ”are specified, and the congestion state of those SM30“ SM1 ”and UP40“ UP1 ”is specified.

  At this time, the congestion state specifying unit 23 may determine the congestion state by measuring a communication delay time between the MM 20 and the SM 30 or the UP 40, or may be notified of the congestion state from the SM 30 or the UP 40 or the like. Good. In addition, the congestion state specifying unit 23 may specify the congestion state every time a session request is received, or may perform it in advance (at an arbitrary timing such as periodically).

  The request reply unit 25 returns a response to the UE 10 in response to the attach request or session request from the UE 10. That is, in response to the attach request, when the congestion state of the network to which the slice is connected is specified as “congested”, the request reply unit 25 returns an attach rejection (Attach Reject) including a back-off timer. To do. This attach rejection is a signal for requesting retransmission of the attach request, and a back-off timer included in the attach rejection is a timer for instructing the timing of retransmission of the attach request. On the other hand, if the congestion state of the network to which the slice is connected is specified as “no congestion” in response to the attach request, the attachment completion notification (Attach) is set after the mobility management function unit 21 sets the control data communication path. (Accept) is returned. In addition, in response to the session request, the request reply unit 25 returns a session rejection (PDU Session Reject) including a back-off timer when the congestion state of the slice is specified as “congested”. The session rejection is a signal for requesting retransmission of the session request, and the back-off timer included in the session rejection is a timer for instructing the timing of retransmission of the session request. On the other hand, when the congestion state of the slice is specified as “no congestion” in response to the session request, a session completion notification (PDU Session Accept) is returned after the mobility management function unit 21 sets the user data communication path. To do.

  Next, the communication path setting process of the mobile communication system 1 described above will be described, and the congestion control method according to the present embodiment will be described in detail. FIG. 6 is a sequence diagram showing a procedure for setting a communication route for control data by the mobile communication system 1, and FIG. 7 is a sequence diagram showing a procedure for setting a communication route for user data by the mobile communication system 1. FIG.

  First, the control data communication path setting process will be described with reference to FIG. First, it is assumed that the congestion state of the DNN “DNN1” to which the slice “Slice # 1” is connected is detected as “congested” by the congestion state specifying unit 23 of the MM 20 in advance (step S101). In this state, when the request receiving unit 22 of the MM 20 receives an attach request including the slice type information “Slice # 1” and DNN “DNN1” from the UE 10 (step S102), the congestion state specifying unit 23 of the MM 20 Thus, the congestion state of the DNN “DNN1” to which the slice “Slice # 1” is connected is specified (step S103). As a result, when the congestion state of the connected DNN “DNN1” is specified as “congested”, the attachment rejection including the back-off timer is sent from the request reply unit 25 of the MM 20 to the UE 10. Is returned (step S104). Note that the congestion state of the MM 20 itself may be detected in step S101, the congestion state of the MM 20 itself may be specified in step S103, and attach rejection may be returned based on the congestion state of the MM 20 itself in step S104.

  Next, user data communication path setting processing will be described with reference to FIG. First, the SM 30 “SM1” assigned to the slice “Slice # 1” is notified that there is a congestion state (step S201), and based on this notification, the congestion state specifying unit 23 of the MM 20 previously determines the slice “Slice”. Assume that the congestion state of “# 1” is detected as “congested” (step S202). In this state, when a request for a session including slice type information “Slice # 1” and DNN “DNN1” is received from the UE 10 by the request receiving unit 22 of the MM 20 (step S203), the congestion state specifying unit 23 of the MM 20 Thus, the congestion state of the slice “Slice # 1” is specified (step S204). As a result, when the congestion state of the slice “Slice # 1” is specified as “congested”, a session rejection including a back-off timer is issued from the request reply unit 25 of the MM 20 to the UE 10. A reply is made (step S205). On the other hand, when the session receiving request including the slice type information “Slice # 2” and DNN “DNN3” is received from the UE 10 by the request receiving unit 22 of the MM 20 (Step S206), the congestion state specifying unit 23 of the MM 20 After the congestion state of “Slice # 2” is identified as “no congestion” and the PDU-ID is allocated by the mobility management function unit 21 of the MM 20, the PDU-ID, slice type information “Slice # 2” and DNN “DNN3” Is transmitted to the SM 30 “SM2” assigned to the corresponding slice “Slice # 2” (step S207). Thereafter, after a process for setting a communication path between the UE 10 and the SM 30 “SM 2” is executed, a session completion notification is returned from the SM 30 “SM 2” to the UE 10 via the MM 20 (steps S 208 and S 209). .

  Next, the effect of the mobile communication system 1 and the congestion control method of this embodiment will be described. According to the mobile communication system 1 described above, when an attach request or a session request is received from the UE 10, backoff is performed in units of slices based on the congestion state of the slice or the congestion state of the network to which the slice is connected. A retransmission request including a timer is returned to the UE 10. As a result, it is possible to perform efficient communication by realizing congestion control in units of slices in which a tendency of communication congestion is likely to appear.

  Further, in the above embodiment, management information for specifying a slice connected to the DNN is held for each DNN of the connection destination, and the DNN of the connection destination of the slice is specified based on the management information, and the congestion state of the DNN Is identified. By doing so, the congestion state of the network to which the slice is connected is appropriately identified. As a result, congestion control in units of slices is appropriately realized.

  Further, in the above embodiment, management information for specifying slices assigned to a plurality of SMs and a plurality of UPs is held, and based on the management information, SMs or UPs assigned to slices are specified, and the SMs or UPs Is identified as the congestion state of the slice. By doing so, the congestion state of the slice is appropriately identified. As a result, congestion control in units of slices is appropriately realized.

  Although the present embodiment has been described in detail above, it will be apparent to those skilled in the art that the present embodiment is not limited to the embodiment described in this specification. The present embodiment can be implemented as a modification and change without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present embodiment.

  For example, in the above-described embodiment, the SM or UP may be configured to identify a congestion state and control a reply to the UE 10 for a session request based on the congestion state. Hereinafter, a configuration in the case where the SM has a congestion state specifying function and a control function for returning a session request will be described. FIG. 8 is a block diagram showing a hardware configuration of an SM 30A according to a modification of the SM 30 of the above-described embodiment, and FIG. 9 is a block diagram showing a functional configuration of the SM 30A.

  As shown in FIG. 9, the SM 30A includes, as functional components, a session management function unit 31, a request receiving unit 32, a congestion state specifying unit 33, an information holding unit (network information holding unit) 34, and a request reply unit ( A retransmission request transmission unit) 35.

  The block diagram shown in FIG. 9 shows functional unit blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one device physically and / or logically coupled, and two or more devices physically and / or logically separated may be directly and / or indirectly. (For example, wired and / or wireless) and may be realized by these plural devices.

  For example, the SM 30A in this modification may function as a computer that performs the processing of the SM 30A in this modification. FIG. 8 shows an example of the hardware configuration of the SM 30A according to this modification. Since this hardware configuration is the same as the configuration of FIG. 2, detailed description thereof is omitted. The session management function unit 31, the request reception unit 32, the congestion state identification unit 33, the request reply unit 35, and the like illustrated in FIG. 9 may be realized by the processor 1001. The session management function unit 31 may be realized by a control program stored in the memory 1002 and operated by the processor 1001, and may be realized similarly for other functional blocks. The information holding unit 34 and the like may be realized by the storage 1003. The request receiving unit 32, the request replying unit 35, and the like may be realized by the communication device 1004.

  Next, the function of each functional unit of the SM30A of this modification will be described.

  The session management function unit 31 is a function unit that manages a session of a communication path (bearer) between the UE 10 and the UP 40 located in the mobile communication system 1. Specifically, bearer setting processing is executed in response to a session request from the MM 20.

  The request reception unit 32 receives a session request (PDU Session Request) for requesting connection establishment of a communication path for user data from the UE 10 via the MM 20. At this time, the request reception unit 32 includes session identification information (PDU-ID) allocated by the MM 20 in the session request, and service type information (slice identification information) or slice type information (slice identification information) for identifying a slice. ) And DNN indicating the address of the connection destination node. In response to the reception of the session request by the request reception unit 32, the session management function unit 31 performs a process for setting a user data session between the UE 10 and the UP 40 via the corresponding slice.

  When the session request is received by the request receiving unit 32, the congestion state specifying unit 33 identifies a slice corresponding to service type information or slice type information included in the session request, and congestion of the network to which the slice is connected Identify the state. At this time, the congestion state specifying unit 33 specifies the network to which the slice is connected by referring to the network management information held in the information holding unit 34, and specifies the congestion state of the specified network.

  In FIG. 10, (a) part and (b) part each show an example of the data configuration of the network management information held in the information holding part 34. In the example of the network management information shown in part (a) of FIG. 10, slice type information for specifying a slice connected to the network for each of DNN “DNN1” and “DNN2” specifying a connection destination network. “Slice # 1” and “Slice # 2” are associated with session identification information (PDU-ID) “PDU session # 1” and “PDU session # 2” for identifying a session set through the slice. In the example of the network management information shown in part (b) of FIG. 10, a slice for specifying a slice connected to the network with respect to DNN “DNN2” and “DNN2” for specifying a connection destination network. Type information “Slice # 1”, “Slice # 2” and session identification information (PDU-ID) “PDU session # 1”, “PDU session # 2” for identifying a session set through the slice It is associated with. In this way, a plurality of slices can be connected to the same DNN. In addition, a plurality of sessions corresponding to slices can be set for the same DNN. When the attach request including the slice type information “Slice # 1” is received, the congestion state specifying unit 33 refers to the network management information shown in the (a) part of FIG. 10 and determines the slice “Slice # 1”. The DNN “DNN1” of the connection destination is specified, and the congestion state of the DNN “DNN1” is specified.

  At this time, the congestion state specifying unit 33 may determine the congestion state by measuring the communication delay time between the SM 30A and the DNN, or may be notified of the congestion state from the DNN or the UP 40 or the like. Further, the congestion state specifying unit 33 may specify the congestion state every time a session request is received, or may perform it in advance (at an arbitrary timing such as periodically). In addition, the congestion state specifying unit 33 may specify the DNN of the connection destination of the slice based on the DNN included in the session request, and specify the congestion state of the specified DNN.

  In addition, when the session request is received by the request receiving unit 32, the congestion state specifying unit 33 identifies the slice corresponding to the service type information or slice type information included in the session request, and the congestion state of the slice itself Is also specified. At this time, the congestion state specifying unit 33 specifies the congestion state of its own SM 30A or UP 40 assigned to the identified slice.

  The congestion state specifying unit 33 may determine the congestion state based on the congestion state of its own SM 30A, or may be notified of the congestion state of the UP 40 or the like from the UP 40 or the like assigned to the slice to be determined. For example, the congestion state is determined by determining whether or not the communication bandwidth allocated to the slice is congested. Further, the congestion state specifying unit 33 may specify the congestion state every time a session request is received, or may perform it in advance (at an arbitrary timing such as periodically).

  The request reply unit 35 returns a response to the UE 10 via the MM 20 in response to the session request from the MM 20. That is, in response to the session request, when the congestion state of the network to which the slice is connected or the congestion state of the slice itself is specified as “congested”, the request reply unit 35 includes a session rejection (including a backoff timer) PDU session Reject) is returned. The session rejection is a signal for requesting retransmission of the session request, and the back-off timer included in the session rejection is a timer for instructing the timing of retransmission of the session request. On the other hand, if the congestion state of the network to which the slice is connected and the congestion state of the slice itself are specified as “no congestion” in response to the session request, the session management function unit 31 sets the user data communication path. , A session completion notification (PDU session Accept) is returned.

  Next, communication path setting processing of the mobile communication system 1 in the above-described modification will be described, and the congestion control method according to the modification will be described in detail. FIG. 11 and FIG. 12 are sequence diagrams showing a procedure of user data communication path setting processing by the mobile communication system 1 according to the present modification.

  First, a user data communication path setting process based on the DNN congestion state will be described with reference to FIG.

  First, a session request including slice type information “Slice # 1” and DNN “DNN1” is transmitted from the UE 10 to the MM 20 (step S301). Then, the SM 30A allocated to the slice specified by the slice type information included in the session request is determined by the MM 20, and a PDU-ID is allocated to the session between the UE 10 and the UP 40 (step S302). . Next, when the request receiving unit 32 of the SM 30A receives a session request including the PDU-ID, the slice type information “Slice # 1”, and the DNN “DNN1” from the MM 20 (Step S303), The congestion state identification unit 33 identifies the congestion state of the DNN “DNN1” to which the slice “Slice # 1” is connected (step S304). As a result, when the congestion state of the DNN “DNN1” at the connection destination is specified as “congested”, session rejection including a back-off timer is sent from the request reply unit 35 of the SM 30A to the MM 20. Is returned (step S305). On the other hand, in MM 20, the setting is changed so as to return a session rejection for all session requests from DN 10 to DNN “DNN1”, and the PDU-ID allocated in step S302 is deleted ( Step S306). Then, a session rejection including a newly set back-off timer is returned from the MM 20 to the UE 10 (step S307).

  On the other hand, from the UE 10 to the MM 20, the slice type information “Slice # 1” and DNN “DNN1” and the slice type information “Slice # 2” and DNN “DNN2” are simultaneously requested to set up two sessions. Assume that a session request is transmitted (step S308). In this case, the MM 20 determines the two SMs 30A “SM1” and “SM2” allocated to the two slices specified by the slice type information included in the session request, and sets them between the UE 10 and the UP 40. A PDU-ID is assigned to each of the two sessions. Next, a session request including the PDU-ID, slice type information “Slice # 1”, and DNN “DNN1” is received from the MM 20 by the determined request receiving unit 32 of one SM 30A (step S309). ). On the other hand, a session request including the PDU-ID, the slice type information “Slice # 2”, and the DNN “DNN2” is received from the MM 20 by the determined request receiving unit 32 of the other SM 30A (step S310). At this time, in each of the two SMs 30A, the respective congestion states of DNN “DNN1” and DNN “DNN2” are detected (steps S311 and S312).

  Then, the congestion state identifying unit 33 of one SM 30A identifies the congestion state of the DNN “DNN1” to which the slice “Slice # 1” is connected (step S313). As a result, when the congestion state of the DNN “DNN1” of the connection destination is specified as “congested”, a back-off timer (SM1 back-off timer) is sent from the request reply unit 35 of one SM 30A to the MM 20. The session rejection including it is returned (step S314). Further, the congestion state of the DNN “DNN2” to which the slice “Slice # 2” is connected is specified by the congestion state specifying unit 33 of the other SM 30A (step S315). As a result, when the congestion state of the DNN “DNN2” at the connection destination is specified as “congested”, a back-off timer (SM2 back-off timer) is sent from the request return unit 35 of the other SM 30A to the MM 20. The session rejection including it is returned (step S316).

  On the other hand, in the MM 20, the setting is changed so as to return a session rejection for all the session requests for the DNN “DNN1” and the DNN “DNN2” from the UE 10, and two PDU-IDs that have already been allocated. Is deleted (step S317). Then, session rejection including two newly set back-off timers (SM1 back-off timer, SM2 back-off timer) is returned from MM 20 to UE 10 (step S318).

  Next, a user data communication path setting process based on the congestion state of the slice will be described with reference to FIG.

  Here, it is assumed that the slice “Slice # 1” in the SM 30A “SM1” assigned to the slice “Slice # 1” is detected in advance (step S401). In this state, a session request including slice type information “Slice # 1” and DNN “DNN1” is transmitted from the UE 10 to the MM 20 (step S402). Then, the SM 30A allocated to the slice specified by the slice type information included in the session request is determined by the MM 20, and a PDU-ID is allocated to the session between the UE 10 and the UP 40 (step S403). . Next, when the request reception unit 32 of the SM 30A receives a session request including the PDU-ID, the slice type information “Slice # 1”, and the DNN “DNN1” from the MM 20 (step S404), the SM 30A The congestion state identification unit 33 identifies the congestion state of the slice “Slice # 1” (step S405). As a result, when the congestion state of the slice “Slice # 1” is specified as “congested”, a session rejection including a back-off timer is issued from the request reply unit 35 of the SM 30A to the MM 20. A reply is made (step S406). On the other hand, in MM 20, the setting is changed so as to return session rejection for all session requests from UE 10 for slice “Slice # 1”, and the PDU-ID allocated in step S403 is deleted. (Step S407). A session rejection including a newly set back-off timer is returned from the MM 20 to the UE 10 (step S408).

  On the other hand, it is assumed that a session request including slice type information “Slice # 2” and DNN “DNN3” is transmitted from the UE 10 to the MM 20 (step S409). Then, the SM 30A allocated to the slice specified by the slice type information included in the session request is determined by the MM 20, and a PDU-ID is allocated to the session between the UE 10 and the UP 40 (step S410). . Next, when the request reception unit 32 of the SM 30A receives a session request including the PDU-ID, the slice type information “Slice # 2”, and the DNN “DNN3” from the MM 20 (step S411), The congestion state identification unit 33 identifies the congestion state of the slice “Slice # 2” (step S412). As a result, when the congestion state of the slice “Slice # 2” is identified as “no congestion”, a session completion notification is returned from the request return unit 35 of the SM 30A to the MM 20 (step S413). Then, a session completion notification is transferred from the MM 20 to the UE 10 (step S414).

  Also according to the above-described modification, when a session request is received from the UE 10, a retransmission request is returned to the UE 10 on a slice basis based on the congestion state of the slice or the congestion state of the network to which the slice is connected. As a result, it is possible to perform efficient communication by realizing congestion control in units of slices in which a tendency of communication congestion is likely to appear.

  The notification of information is not limited to the aspect / embodiment described in the present specification, and may be performed by other methods. For example, information notification includes physical layer signaling (for example, DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (for example, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), It may be implemented by broadcast information (MIB (Master Information Block), SIB (System Information Block))), other signals, or a combination thereof. The RRC signaling may be referred to as an RRC message, and may be, for example, an RRC connection setup message, an RRC connection reconfiguration message, or the like.

  Each aspect / embodiment described herein includes LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G, 5G, FRA (Future Radio Access), W-CDMA. (Registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, UWB (Ultra-WideBand), The present invention may be applied to a Bluetooth (registered trademark), a system using other appropriate systems, and / or a next generation system extended based on these systems.

  As long as there is no contradiction, the order of the processing procedures, sequences, flowcharts, and the like of each aspect / embodiment described in this specification may be changed. For example, the methods described herein present the elements of the various steps in an exemplary order and are not limited to the specific order presented.

  Information or the like can be output from the upper layer (or lower layer) to the lower layer (or upper layer). Input / output may be performed via a plurality of network nodes.

  Input / output information and the like may be stored in a specific location (for example, a memory) or may be managed by a management table. Input / output information and the like can be overwritten, updated, or additionally written. The output information or the like may be deleted. The input information or the like may be transmitted to another device.

  The determination may be performed by a value represented by 1 bit (0 or 1), may be performed by a true / false value (Boolean: true or false), or may be performed by comparing numerical values (for example, a predetermined value) Comparison with the value).

  Each aspect / embodiment described in this specification may be used independently, may be used in combination, or may be switched according to execution. In addition, notification of predetermined information (for example, notification of being “X”) is not limited to explicitly performed, but is performed implicitly (for example, notification of the predetermined information is not performed). Also good.

  Software, whether it is called software, firmware, middleware, microcode, hardware description language, or other names, instructions, instruction sets, code, code segments, program codes, programs, subprograms, software modules , Applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc. should be interpreted broadly.

  Also, software, instructions, etc. may be transmitted / received via a transmission medium. For example, software may use websites, servers, or other devices using wired technology such as coaxial cable, fiber optic cable, twisted pair and digital subscriber line (DSL) and / or wireless technology such as infrared, wireless and microwave. When transmitted from a remote source, these wired and / or wireless technologies are included within the definition of transmission media.

  Information, signals, etc. described herein may be represented using any of a variety of different technologies. For example, data, commands, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these May be represented by a combination of

  Note that the terms described in this specification and / or terms necessary for understanding this specification may be replaced with terms having the same or similar meaning.

  In addition, information, parameters, and the like described in this specification may be represented by absolute values, may be represented by relative values from a predetermined value, or may be represented by other corresponding information. . For example, the radio resource may be indicated by an index.

  The names used for the parameters described above are not limiting in any way.

  As used herein, the terms “determining” and “determining” may encompass a wide variety of actions. “Judgment”, “decision” can be, for example, calculating, computing, processing, deriving, investigating, looking up (eg, table, database or another (Searching in the data structure), and confirming (ascertaining) what has been confirmed may be considered as “determining” or “determining”. In addition, “determination” and “determination” include receiving (for example, receiving information), transmitting (for example, transmitting information), input (input), output (output), and access. (accessing) (e.g., accessing data in a memory) may be considered as "determined" or "determined". In addition, “determination” and “decision” means that “resolving”, “selecting”, “choosing”, “establishing”, and “comparing” are regarded as “determining” and “deciding”. May be included. In other words, “determination” and “determination” may include considering some operation as “determination” and “determination”.

  The terms “connected”, “coupled”, or any variation thereof, means any direct or indirect connection or coupling between two or more elements and It can include the presence of one or more intermediate elements between two “connected” or “coupled” elements. The coupling or connection between the elements may be physical, logical, or a combination thereof. As used herein, the two elements are radio frequency by using one or more wires, cables and / or printed electrical connections, and as some non-limiting and non-inclusive examples By using electromagnetic energy, such as electromagnetic energy having a wavelength in the region, microwave region, and light (both visible and invisible) region, it can be considered to be “connected” or “coupled” to each other.

  As used herein, the phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” means both “based only on” and “based at least on.”

  As long as “include”, “comprising”, and variations thereof, are used in the specification or claims, these terms are similar to the term “comprising”. It is intended to be comprehensive. Furthermore, the term “or” as used herein or in the claims is not intended to be an exclusive OR.

  In this specification, a plurality of devices are also included unless there is only one device that is clearly present in context or technically.

  Throughout this disclosure, the plural is included unless the context clearly indicates one.

  The present invention is intended to use a mobile communication system and a congestion control method, realizes congestion control in units of slices, and enables communication efficiency.

  DESCRIPTION OF SYMBOLS 1 ... Mobile communication system, 10 ... UE (mobile communication terminal), 20 ... MM (mobility management function part), 30a, 30b, 30 ... SM (session management function part), 40a, 40b, 40 ... UP (user (Data transmission function unit), 21 ... mobility management function unit, 22 ... request receiving unit, 23 ... congestion state specifying unit, 24 ... information holding unit (network information holding unit, slice allocation information holding unit), 25 ... request reply unit ( (Retransmission request transmission unit), 31 ... Session management function unit, 32 ... Request reception unit, 33 ... Congestion state identification unit, 34 ... Information holding unit (network information holding unit), 35 ... Request reply unit (retransmission request transmission unit), SLa, SLb ... slice.

Claims (6)

A mobility management function unit for managing mobility of the mobile communication terminal, a plurality of session management function units for managing sessions of the mobile communication terminal, and a plurality of user data used for services to the mobile communication terminal Mobile communication in which a plurality of slices which are a plurality of virtual networks are assigned to the plurality of session management function units and the plurality of user data transmission function units A system,
When receiving a connection establishment request including slice specifying information for specifying the slice from the mobile communication terminal, and the congestion of the slice or the network to which the slice is connected is specified based on the slice specifying information A mobile communication system comprising a retransmission request transmission unit that transmits a retransmission request for requesting retransmission of the connection establishment request to the mobile communication terminal. A network information holding unit for holding management information for identifying a slice connected to the network for each of the connection destination networks;
Congestion that identifies the network to which the slice is connected by referring to the management information held in the network information holding unit based on the slice identification information included in the connection establishment request, and identifies the congestion state of the network A state identification part;
The mobile communication system according to claim 1, further comprising: A slice assignment information holding unit for holding management information for identifying slices assigned to the plurality of session management function units and the plurality of user data transmission function units;
The session management function unit or the user data transmission function unit assigned to the slice is specified by referring to the management information held in the slice assignment information holding unit based on the slice specification information included in the connection establishment request A congestion state specifying unit that specifies the congestion state of the session management function unit or the user data transmission function unit as the congestion state of the slice;
The mobile communication system according to claim 1, further comprising: The mobility management function unit is provided with the retransmission request transmission unit.
The mobile communication system according to any one of claims 1 to 3. The session management function unit is provided with the retransmission request transmission unit.
The mobile communication system according to any one of claims 1 to 3. A mobility management function unit for managing mobility of the mobile communication terminal, a plurality of session management function units for managing sessions of the mobile communication terminal, and a plurality of user data used for services to the mobile communication terminal Mobile communication in which a plurality of slices which are a plurality of virtual networks are assigned to the plurality of session management function units and the plurality of user data transmission function units A congestion control method in a system,
When receiving a connection establishment request including slice specifying information for specifying the slice from the mobile communication terminal, and the congestion of the slice or the network to which the slice is connected is specified based on the slice specifying information A congestion control method for transmitting a retransmission request for requesting retransmission of the connection establishment request to the mobile communication terminal.

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